Los Angeles Dodgers’ Yasiel Puig steals third base against the Colorado Rockies in the seventh inning of a baseball game Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Los Angeles Dodgers second baseman Brian Dozier, left, throws over Colorado Rockies’ Carlos Gonzalez after forcing him out at second base on the front end of a double play hit into by Trevor Story during the sixth inning of a baseball game Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Colorado Rockies third baseman Ryan McMahon left, applies a late tag as Los Angeles Dodgers’ Justin Turner (10) pulls into third base with an RBI-triple in the first inning of a baseball game Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Los Angeles Dodgers’ Yasiel Puig gestures as he crosses home plate after hitting a solo home run off Colorado Rockies starting pitcher Kyle Freeland in the second inning of a baseball game Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Colorado Rockies starting pitcher Kyle Freeland, front, reacts after giving up a solo home run to Los Angeles Dodgers’ Yasiel Puig, back, in the second inning of a baseball game Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Los Angeles Dodgers’ Manny Machado follows the flight of his double off Colorado Rockies starting pitcher Kyle Freeland during the first inning of a baseball game Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Los Angeles Dodgers’ Justin Turner follows the flight of his RBI-triple off Colorado Rockies starting pitcher Kyle Freeland in the first inning of a baseball game Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Colorado Rockies starting pitcher Kyle Freeland works against the Los Angeles Dodgers in the first inning of a baseball game Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Los Angeles Dodgers left fielder Matt Kemp warms up before a baseball game against the Colorado Rockies, Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Los Angeles Dodgers second baseman Chase Utley, left, jokes with center fielder Enrique Hernandez as they warm up before a baseball game against the Colorado Rockies, Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Los Angeles Dodgers center fielder Enrique Hernandez leans over the dugout rail while waiting to warm up before a baseball game against the Colorado Rockies, Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Colorado Rockies catcher Chris Iannetta waits to bat as he warms up before a baseball game against Los Angeles Dodgers, Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

Colorado Rockies third baseman Nolan Arenado, center, jokes with teammates as they warm up before a baseball game against the Los Angeles Dodgers, Saturday, Aug. 11, 2018, in Denver. (AP Photo/David Zalubowski)

For the second consecutive night, former Mater Dei two-sport star Ryan McMahon drove home the point. This time, the Dodgers were only one out away from taking sole possession of first place in the National League West when McMahon hit a three-run walkoff home run to give the Colorado Rockies a 3-2 victory Saturday night.

On Friday, McMahon hit a two-run home run in the seventh inning that lifted the Rockies to a 5-4 victory.

In both cases, the victims – left-hander Zac Rosscup on Friday and right-hander J.T. Chargois on Saturday – were pitching in situations they probably would not have been in if Dodgers closer Kenley Jansen were available.

But Jansen is sidelined, being treated for an irregular heartbeat, leaving the Dodgers’ bullpen with no back.

“Obviously you don’t have that guy who’s proven to get outs in the ninth inning. That’s where we’re at right now,” Dodgers manager Dave Roberts said. “We talked about ‘closer-by-committee’ and giving guys opportunities and the matchups that we feel will give us the best opportunity to get those last three outs.”

After rookies Walker Buehler and Caleb Ferguson combined to get a shutout into a ninth inning at Coors Field, Roberts convened the committee.

Scott Alexander has been the Dodgers’ most reliable reliever and the leading candidate to assume the closer role in Jansen’s absence. But that is not the Dodgers’ plan. Matchup-based decisions are.

Alexander struck out the left-handed Carlos Gonzalez but gave up a double to right-handed Trevor Story. Nolan Arenado did not start the game because of a sore shoulder. But when Rockies manager Buddy Black sent Arenado up as a pinch-hitter, Roberts wanted a right-hander.

But his best right-handed reliever, Dylan Floro, was unavailable based on usage recently – he pitched in three of the previous four games and warmed up in the other. So Roberts went with Chargois.

“I just felt Arenado does a lot of damage against lefties. There’s some history there,” Roberts said. “You’ve got Desmond behind him. It’s a great runway for Shaggy who’s shown the ability to consistently get righties out, put them on the ground or strike them out. You got that. You got an out. I just felt it was the right play.”

The history between Alexander and Arenado is minimal – four plate appearances, one hit (a home run) and a walk.

“Arenado has homered off him before so he has put the ball in the air off him,” Roberts said, defending his decision. “You look at the ground-ball ratio and the success with Chargois — it’s pretty stark that Chargois has a better chance.

“Neither guy has really closed. I just felt to put both those guys in a position to have success, that was the right decision.”

Based on the results, it wasn’t.

Chargois fell behind 3-and-1 then hit Arenado in the left hip with a slider. Perhaps Chargois’ best pitch, he had difficulty controlling his slider Saturday.

“That’s fair to say. He wasn’t as sharp with it today. But that happens,” Dodgers catcher Austin Barnes said. “He’s still got a good mix with his sinker. We should still be able to get guys out.”

Chargois got Ian Desmond to bounce a ball up the middle. Second baseman Brian Dozier made a sprawling stop then flipped the ball from his glove to Manny Machado while lying on the ground. Dozier made the same play for one of three double plays the Dodgers turned for Buehler.

This one only went for a single out and brought up the left-handed McMahon. Roberts’ only left-handed option to face him was two-handed Pat Venditte.

He left Chargois in and McMahon clubbed his 1-and-0 fastball over the scoreboard in right field.

“Arenado, we were trying to attack with sliders and get ahead of him,” Chargois said. “Battled with Desmond and got a ground ball. Unfortunately, it was in a place where we couldn’t get the double play.

“Left that (last) pitch up and he hit it.”

A win either Friday or Saturday would have moved the Dodgers ahead of the Arizona Diamondbacks and alone atop the division. Their bullpen wouldn’t let it happen.

“We have confidence in all these guys,” Barnes said. “I think everybody is capable of getting big outs in big situations. Obviously it was a luxury having Kenley for so long. He’s one of the best in the game. But we’re confident in all these guys stepping up for us.”

Bill Plunkett has covered everything from rodeo to Super Bowls to boxing (yeah, I was there the night Mike Tyson bit Evander Holyfield's ear off) during a career that started far too long ago to mention and eventually brought him to the OC some time last century (1999 actually). He has been covering Major League Baseball for the Orange County Register since 2003, spending time on both the Angels and Dodgers beats.